Anti-proliferative and anti-metastatic activities of marine sponges collected from the South Australian coastline

This study was to search for novel chemotherapeutic compounds from marine sponges collected from the coastline of South Australia. Non-polar and polar extracts from twelve sponge species were screened for anti-cancer activity against three types of human cancer cell lines: colon cancer DLD-1, lung cancer A-549, and prostate cancer DU-145. Using non-polar extracts, ten out of twelve species tested showed anti-proliferative effect on all three cell lines tested, especially A-549, as detected by the Crystal Violet assay. The IC50 values ranged from 1.0 to 40 µg/ml. However, no significant anti-proliferative effect was observed after treatment with polar extracts. To identify the active compounds, the most active extract from the sponge Acarnid sp. was selected for fractionation using n-hexane (F1), dichloromethane (F2), butanol (F3), 50% methanol (F4), and 100% methanol (F5). The cytotoxicity of each fraction was tested on the A-549 cell line. F2 and F3 were found to be active, with IC50 values of 0.5 and 5 µg/ml, respectively. Anti-metastatic activity of F2 and F3 on A-549 cell line was investigated at non-toxic concentrations (0-0.25 µg/ml for F2 and 0-1.25 µg/ml for F3). Treatment with F2 at 0.25 µg/ml at 48 h inhibited the abilities of motility (approximately 40%), migration (57%), and invasion (72%) of A-549 cells compared with the untreated control, as detected by the Wound Healing, Migration and Matrigel Invasion Boyden chamber assays. However, F3 did not show anti-metastatic activity under the tested conditions. Taken together, the sponge extracts exhibit potential anti-cancer activity. These extracts are currently undergoing further analysis to identify the active constituents and to investigate the underlying anti-cancer mechanisms.